Personal computers are widely used in consumer and commercial environments. Personal computers include, but are not limited to, IBM.RTM. and IBM-compatible computers which operate in a Windows.RTM. or OS/2.RTM. environment. Personal computers can also include workstations operating in a Unix.RTM. or other environment. As is well known to those having skill in the art, a personal computer includes a central processing unit (also referred to as a "system unit") and a user interface that is responsive to user input and to the central processing unit. The user interface generally includes a display, a keyboard, and a pointing device such as a mouse. The personal computer also includes persistent storage such as a hard disk drive that stores programs and data. An operating system such as Windows 95.RTM., OS/2.RTM. or Unix.RTM. is also stored in the persistent storage. A plurality of applications programs such as computer games or an office suite are also generally stored in the persistent storage.
Personal computers also may include a network interface application that communicates with a server over a network. The network interface application may be an Internet interface that communicates with the Internet using HTTP or other protocols. Examples of network interface applications include Netscape.RTM. Navigator.RTM. and Microsoft.RTM. Internet Explorer.RTM..
As personal computers and their application programs become more sophisticated, it is becoming increasingly clear that their total cost of ownership, including hardware and software maintenance and upgrades, may be much larger than the initial cost of the hardware and software itself. In fact, up to $35,000 or more may be spent annually to maintain each personal computer in a corporate environment.
Network computers have been proposed in order to reduce this overall cost of ownership. Network computers generally do not require a user or administrator to install software on the computer. Rather, all software is loaded from a network server when the network computer is started or when needed during a session. The overall specifications for network computers are described in a document entitled Profile Definition: Network Computer, X/Open, Document Number: X975, published by The Open Group, Berkshire, UK (1997), the disclosure of which is hereby incorporated herein by reference. Network computers have presently been announced and/or shipped by IBM Corp. (Network Station, Series 100, 300 and 1000), Sun Microsystems (Java Station), Oracle (N.C.), Neoware (Neostation), Wyse (Winterm), Acorn (Netstation) and Corel Computer Corp. (Corel Video Network Computer).
Programs for network computers are typically written in Java. As is well known to those having skill in the art, Java programs, in compiled form, are generally portable and will generally run on a wide range of computers and operating systems. Java programs support referencing Universal Resource Locator (URL) identifiers with content types of audio/basic, audio/x-wav, image/gif and image/jpeg. Java provides a machine dependent desktop for executing machine independent applets.
Network computers are also known as "diskless computers" because they generally do not include persistent storage such as a floppy disk, hard disk or CD-ROM. Due to the lack of a disk, all programs and data, except for a small loading program, are obtained from the server.
FIG. 1 is a simplified block diagram of a network computer that is connected to a server using an Internet connection. As shown in FIG. 1, network computer 100 includes a central processing unit 102 (also referred to as a "system unit") and a user interface including a display 104, a keyboard 106, and a pointing device (mouse) 108. As also shown in FIG. 1, the network computer does not generally include persistent storage for storing programs and data. A limited amount of volatile storage such as Random Access Memory (RAM) may be used to temporarily store applications and data while the network computer is running, but this volatile storage loses its information when the network computer is turned off. The network computer may also include permanent storage such as Read Only Memory, which may store a URL identifier to identify the server with which the computer works. The permanent storage may also include a base key which is used for security purposes.
Network computer 100 also includes a network interface 110 that allows the computer to communicate with a server 120 using a network such as the Internet 130. As shown in FIG. 1, server 120 generally includes Hypertext Transfer Protocol (HTTP), Bootstrap Protocol (BOOTP), Dynamic Host Configuration Protocol (DHCP), Network File System (NFS) and Trivial File Transfer Protocol (TFTP) servers. The server 120 also stores operating system images and a Java Runtime Environment (JRE). A Java desktop and other applications may also be included. Other non-Java related applications may also be included.
During initialization, the network computer typically carries out a process similar to that of a personal computer. The network computer begins by performing a power on self test (POST) followed by execution of program code which loads the operating system from the network server. The operating system is then initialized and any further processing is performed utilizing the operating system (e.g. loading of the JRE). The program code which resides on the network computer is often referred to as "firmware" because it is persistently stored in the computer hardware.
In order to load the operating system, the program code which resides on the network computer should be able to initialize the network interface and other peripherals associated with the network computer. Thus, the firmware may have device dependent program code and may be required to change over time. Furthermore, as peripherals are added to the network computer there may be a need to revise the firmware to account for these peripherals. Additionally, the initialization code or the POST procedure may also need to change from that originally provided with the network computer.
Traditionally, firmware and device drivers which reside on a personal computer are updated by installing new firmware or device drivers from a portable storage media such as a floppy disk drive, CDROM, or hard disk. Alternatively, the update would be downloaded from a commonly accessible storage location such as a bulletin board or Internet web site to a persistent local storage device. This process, essentially replicates the typical process of updating the firmware from a portable storage media by providing the firmware update on persistent storage. In either case, the firmware installation requires a persistent local storage media because the update would be accomplished by initializing the personal computer (i.e. "booting") from the persistent local storage media. This operation is typically a manual operation which may require user intervention at each personal computer to be updated.
By providing for centralized application management at the server, network computers may reduce the management requirements for a computer network. Furthermore, because the applications of a network computer are centrally managed, a user may move from location to location within the network and still have available the same applications. However, because a network computer has no removable or local mass storage such as hard disk, CDROM or floppy disk drives, updating firmware or device drivers which reside on the network computer may be difficult, labor intensive and in some situations impossible. Furthermore, there is no local storage device to download the update to or to boot from to install the new firmware. Additionally, the download operation may be non-secure and may introduce the possibility that a virus or other corrupted data may be introduced to the computer. Accordingly, a need exists for improvements in updating firmware for network computers.